Re: [PATCH v2 2/3] ACPI: Behave uniquely based on processor declaration definition type

[Myron Stowe <myron.stowe@hp.com>]

On Fri, 2008-10-31 at 09:19 +0800, Zhao Yakui wrote:
> On Fri, 2008-10-31 at 06:13 +0800, Myron Stowe wrote:
> > Associating a Local SAPIC with a processor object is dependent upon the
> > processor object's definition type.  CPUs declared as "Processor" should
> > use the Local SAPIC's 'processor_id', and CPUs declared as "Device"
> > should use the 'uid'.  Note that for "Processor" declarations, even if a
> > '_UID' child object exists, it has no bearing with respect to mapping
> > Local SAPICs (see section 5.2.11.13 - Local SAPIC Structure; "Advanced
> > Configuration and Power Interface Specification", Revision 3.0b).
> > 
> > This patch changes the lsapic mapping logic to rely on the distinction of
> > how the processor object was declared - the mapping can't just try both
> > types of matches irregardless of declaration type and rely on one failing
> > as is currently being done.
> > 
> > Signed-off-by: Myron Stowe <myron.stowe@hp.com>
> > Cc: Alexey Starikovskiy <aystarik@gmail.com>
> > Cc: Zhao Yakui <yakui.zhao@intel.com>
> > ---
> > 
> >  drivers/acpi/processor_core.c |   75 +++++++++++++++++++++++------------------
> >  1 files changed, 42 insertions(+), 33 deletions(-)
> > 
> > diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
> > index 0c670dd..35d33e8 100644
> > --- a/drivers/acpi/processor_core.c
> > +++ b/drivers/acpi/processor_core.c
> > @@ -410,7 +410,7 @@ static int acpi_processor_remove_fs(struct acpi_device *device)
> >  /* Use the acpiid in MADT to map cpus in case of SMP */
> >  
> >  #ifndef CONFIG_SMP
> > -static int get_cpu_id(acpi_handle handle, u32 acpi_id) {return -1;}
> > +static int get_cpu_id(acpi_handle handle, int type, u32 acpi_id) { return -1; }
> >  #else
> >  
> >  static struct acpi_table_madt *madt;
> > @@ -429,27 +429,35 @@ static int map_lapic_id(struct acpi_subtable_header *entry,
> >  }
> >  
> >  static int map_lsapic_id(struct acpi_subtable_header *entry,
> > -		  u32 acpi_id, int *apic_id)
> > +		int device_declaration, u32 acpi_id, int *apic_id)
> >  {
> >  	struct acpi_madt_local_sapic *lsapic =
> >  		(struct acpi_madt_local_sapic *)entry;
> > +	u32 tmp = (lsapic->id << 8) | lsapic->eid;
> > +
> >  	/* Only check enabled APICs*/
> > -	if (lsapic->lapic_flags & ACPI_MADT_ENABLED) {
> > -		/* First check against id */
> > -		if (lsapic->processor_id == acpi_id) {
> > -			*apic_id = (lsapic->id << 8) | lsapic->eid;
> > -			return 1;
> > -		/* Check against optional uid */
> > -		} else if (entry->length >= 16 &&
> > -			lsapic->uid == acpi_id) {
> > -			*apic_id = lsapic->uid;
> > -			return 1;
> > -		}
> > -	}
> > +	if (!(lsapic->lapic_flags & ACPI_MADT_ENABLED))
> > +		return 0;
> > +
> > +	/* Device statement declaration type */
> > +	if (device_declaration) {
> > +		if (entry->length < 16)
> > +			printk(KERN_ERR PREFIX
> > +			    "Invalid LSAPIC with Device type processor (SAPIC ID %#x)\n",
> > +			    tmp);
> > +		else if (lsapic->uid == acpi_id)
> > +			goto found;
> > +	/* Processor statement declaration type */
> > +	} else if (lsapic->processor_id == acpi_id)
> > +		goto found;
> > +
> >  	return 0;
> > +found:
> > +	*apic_id = tmp;
> > +	return 1;
> >  }
> >  
> > -static int map_madt_entry(u32 acpi_id)
> > +static int map_madt_entry(int type, u32 acpi_id)
> >  {
> >  	unsigned long madt_end, entry;
> >  	int apic_id = -1;
> > @@ -470,7 +478,7 @@ static int map_madt_entry(u32 acpi_id)
> >  			if (map_lapic_id(header, acpi_id, &apic_id))
> >  				break;
> >  		} else if (header->type == ACPI_MADT_TYPE_LOCAL_SAPIC) {
> > -			if (map_lsapic_id(header, acpi_id, &apic_id))
> > +			if (map_lsapic_id(header, type, acpi_id, &apic_id))
> >  				break;
> >  		}
> >  		entry += header->length;
> > @@ -478,7 +486,7 @@ static int map_madt_entry(u32 acpi_id)
> >  	return apic_id;
> >  }
> >  
> > -static int map_mat_entry(acpi_handle handle, u32 acpi_id)
> > +static int map_mat_entry(acpi_handle handle, int type, u32 acpi_id)
> >  {
> >  	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> >  	union acpi_object *obj;
> > @@ -501,7 +509,7 @@ static int map_mat_entry(acpi_handle handle, u32 acpi_id)
> >  	if (header->type == ACPI_MADT_TYPE_LOCAL_APIC) {
> >  		map_lapic_id(header, acpi_id, &apic_id);
> >  	} else if (header->type == ACPI_MADT_TYPE_LOCAL_SAPIC) {
> > -		map_lsapic_id(header, acpi_id, &apic_id);
> > +		map_lsapic_id(header, type, acpi_id, &apic_id);
> >  	}
> >  
> >  exit:
> > @@ -510,14 +518,14 @@ exit:
> >  	return apic_id;
> >  }
> >  
> > -static int get_cpu_id(acpi_handle handle, u32 acpi_id)
> > +static int get_cpu_id(acpi_handle handle, int type, u32 acpi_id)
> >  {
> >  	int i;
> >  	int apic_id = -1;
> >  
> > -	apic_id = map_mat_entry(handle, acpi_id);
> > +	apic_id = map_mat_entry(handle, type, acpi_id);
> >  	if (apic_id == -1)
> > -		apic_id = map_madt_entry(acpi_id);
> > +		apic_id = map_madt_entry(type, acpi_id);
> >  	if (apic_id == -1)
> >  		return apic_id;
> >  
> > @@ -533,15 +541,16 @@ static int get_cpu_id(acpi_handle handle, u32 acpi_id)
> >                                   Driver Interface
> >     -------------------------------------------------------------------------- */
> >  
> > -static int acpi_processor_get_info(struct acpi_processor *pr, unsigned has_uid)
> > +static int acpi_processor_get_info(struct acpi_device *device)
> >  {
> >  	acpi_status status = 0;
> >  	union acpi_object object = { 0 };
> >  	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
> > -	int cpu_index;
> > +	struct acpi_processor *pr;
> > +	int cpu_index, device_declaration = 0;
> >  	static int cpu0_initialized;
> >  
> > -
> > +	pr = acpi_driver_data(device);
> >  	if (!pr)
> >  		return -EINVAL;
> >  
> > @@ -562,8 +571,11 @@ static int acpi_processor_get_info(struct acpi_processor *pr, unsigned has_uid)
> >  		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
> >  				  "No bus mastering arbitration control\n"));
> >  
> > -	/* Check if it is a Device with HID and UID */
> > -	if (has_uid) {
> > +	if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_HID)) {
> > +		/*
> > +		 * Declared with "Device" statement; match _UID.
> > +		 * Note that we don't handle string _UIDs yet.
> Looks very good. 
> Can you add the check whether the device.flags.unique_id exists before
> evaluating the _UID object? 
> If not exist, it indicates that the processor definition is incorrect.

The additional check would create a relationship with
'device.flags.unique_id' which seems redundant and would introduce
unnecessary complexity going forward.  While such an additional check
would possibly short circuit the call to 'acpi_evaluate_integer()' -
when FW is in error and a _UID child object does not exist; a case that
is already caught - this code is not in a performance path and thus
seems to yield no benefit.

Was there some other aspect that you were thinking of?

Myron

> Thanks.
> > +		 */
> >  		unsigned long long value;
> >  		status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
> >  						NULL, &value);
> > @@ -571,13 +583,10 @@ static int acpi_processor_get_info(struct acpi_processor *pr, unsigned has_uid)
> >  			printk(KERN_ERR PREFIX "Evaluating processor _UID\n");
> >  			return -ENODEV;
> >  		}
> > +		device_declaration = 1;
> >  		pr->acpi_id = value;
> >  	} else {
> > -		/*
> > -		* Evalute the processor object.  Note that it is common on SMP to
> > -		* have the first (boot) processor with a valid PBLK address while
> > -		* all others have a NULL address.
> > -		*/
> > +		/* Declared with "Processor" statement; match ProcessorID */
> >  		status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
> >  		if (ACPI_FAILURE(status)) {
> >  			printk(KERN_ERR PREFIX "Evaluating processor object\n");
> > @@ -590,7 +599,7 @@ static int acpi_processor_get_info(struct acpi_processor *pr, unsigned has_uid)
> >  		*/
> >  		pr->acpi_id = object.processor.proc_id;
> >  	}
> > -	cpu_index = get_cpu_id(pr->handle, pr->acpi_id);
> > +	cpu_index = get_cpu_id(pr->handle, device_declaration, pr->acpi_id);
> >  
> >  	/* Handle UP system running SMP kernel, with no LAPIC in MADT */
> >  	if (!cpu0_initialized && (cpu_index == -1) &&
> > @@ -662,7 +671,7 @@ static int __cpuinit acpi_processor_start(struct acpi_device *device)
> >  
> >  	pr = acpi_driver_data(device);
> >  
> > -	result = acpi_processor_get_info(pr, device->flags.unique_id);
> > +	result = acpi_processor_get_info(device);
> >  	if (result) {
> >  		/* Processor is physically not present */
> >  		return 0;
> > 
> 
-- 
Myron Stowe                             HP Open Source & Linux Org